21451430687 has 2 divisors, whose sum is σ = 21451430688. Its totient is φ = 21451430686.

The previous prime is 21451430629. The next prime is 21451430701. The reversal of 21451430687 is 78603415412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21451430687 - 2²² = 21447236383 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21451430087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10725715343 + 10725715344.

It is an arithmetic number, because the mean of its divisors is an integer number (10725715344).

Almost surely, 2^21451430687 is an apocalyptic number.

21451430687 is a deficient number, since it is larger than the sum of its proper divisors (1).

21451430687 is an equidigital number, since it uses as much as digits as its factorization.

21451430687 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 161280, while the sum is 41.

The spelling of 21451430687 in words is "twenty-one billion, four hundred fifty-one million, four hundred thirty thousand, six hundred eighty-seven".